1. Field of the Invention
This invention relates to apparatus for storing and reading out data.
2. Description of the Prior Art
Reading apparatus for card-like information carriers are known, which require relative movement between the information carrier and a reading head of the reading apparatus. For example, the information carrier is moved past a stationary reading head, in a guide path of the reading apparatus. The reading head then reads out the coded data which is recorded in one or more data tracks of the information carrier. In many cases, a constant relative speed as between the information carrier and the reading head is required, and this involves substantial technical complexity.
It is known that the requirements for a constant reading speed may be circumvented by arranging a timing track with timing markings on the information carrier. The timing markings are also scanned in the reading apparatus, so marking the respective place, and thus the moment, at which a data bit of the data track is to be read out by the reading head. This makes it possible for the information carrier to be transported manually at any desired speed, when reading out the data. However, by reversing the direction of movement of the information carrier during the reading operation, it is possible to simulate other data, different from the actual data recorded on the data track. This can be prevented if the direction of reading, that is to say, the direction of movement of the information carrier, is detected in the reading apparatus.
A known reading apparatus for identity cards with four data tracks, a parity monitoring track and a timing track, includes a reading head for the timing track, which is displaced relative to the reading heads for the other tracks by such a distance that its reading-out range overlaps with the reading-out ranges of the other heads. A reading direction detector monitors the direction of transportation movement of the card, by means of the signals of all the reading heads, and produces an error signal if the direction of transportation movement is incorrect.